scholarly journals Identification of Cassava Varieties in Ex-Situ Collections and Global Farmer’s Fields: An Update from 1990 to 2020

2021 ◽  
Author(s):  
Luis Augusto Becerra Lopez-Lavalle ◽  
Adriana Bohorquez-Chaux ◽  
Xiaofei Zhang
Keyword(s):  
Genetic Diversity ◽  
Molecular Markers ◽  
Genetic Variability ◽  
Cultivar Identification ◽  
Crop Improvement ◽  
Morphological Characters ◽  
Improved Varieties ◽  
Identification And Characterization ◽  
Made In

The identification of cassava cultivars is important for understanding the crop’s production system, enabling crop improvement practitioners to design and deliver tailored solutions with which farmers can secure high yields and sustainable production. Across the lowland tropics today, a large number improved varieties and landraces of cassava are under cultivation, making it inefficient for breeders and geneticists to set improvement goals for the crop. The identification and characterization of cassava genotypes is currently based on either morphological characters or molecular features. The major aim of cultivar identification is to catalog the crop’s genetic diversity, but a consensus approach has still not been established. Of the two approaches to the identification of variety, morphological characters seem to account for most of the genetic variability reported in cassava. However, these characters must be treated with caution, as phenotypic changes can be due to environmental and climatic conditions as well as to the segregation of new highly heterozygous populations, thus, making the accurate identification of varieties difficult. The use of molecular markers has allowed researchers to establish accurate relationships between genotypes, and to measure and track their heterozygous status. Since the early 1990’s, molecular geneticists working with cassava have been developing and deploying DNA-based tools for the identification and characterization of landraces or improved varieties. Hence, in the last five years, economists and social scientists have adopted DNA-based variety identification to measure the adoption rates of varieties, and to support the legal protection of breeder’s rights. Despite the advances made in the deployment of molecular markers for cassava, multiple platform adoption, as well as their costs and variable throughput, has limited their use by practitioners of crop improvement of cassava. The post-genomic era has produced a large number of genome and transcriptome sequencing tools, and has increased our capacity to develop and deploy genome-based tools to account for the crop’s genetic variability by accurately measuring and tracking allele diversity. These technologies allow the creation of haplotype catalogs that can be widely shared across the cassava crop improvement community. Low-density genome-wide SNP markers might be the solution for the wide adoption of molecular tools for the identification of cultivars or varieties of cassava. In this review we survey the efforts made in the past 30 years to establish the tools for cultivar identification of cassava in farmer’s fields and gene banks. We also emphasize the need for a global picture of the genetic diversity of this crop, at its center of origin in South America.

Assessment of Genetic Diversity of Rheum species (Endangered Medicinal Herb of Indian Himalayan Region) using Molecular Markers

2021 ◽  
Vol 16 (11) ◽  
pp. 147-154
Author(s):  
Anjali Uniyal ◽  
Akhilesh Kumar ◽  
Sweta Upadhyay ◽  
Vijay Kumar ◽  
Sanjay Gupta
Keyword(s):  
Genetic Diversity ◽  
Molecular Markers ◽  
Fragment Length Polymorphism ◽  
Dna Polymorphisms ◽  
Inter Simple Sequence Repeats ◽  
Pharmaceutical Industries ◽  
Endangered Medicinal Herb ◽  
Identification And Characterization ◽  
Simple Sequence

The Rheum species are important medicinal plants that are facing extinction due to their unplanned development and overexploitation by pharmaceutical industries. DNA polymorphisms are not prone to environmental modifications, thus they are widely used for the identification and characterization of plants. The use of different molecular markers has enabled the researchers for the valuation of genetic variability and diversity in its natural zone of distribution. The conventional approach may take several years to yield this information. For the estimation of molecular and genetic variations in geographical zone of distribution, various molecular markers technique are available like RAPD (Randomly Amplified Polymorphic DNA), RFLP (Restriction fragment length polymorphism), ISSR (Inter-Simple Sequence Repeats), SSR and AFLP. The uses of different molecular markers for the study of genetic diversity have been discussed in the review.

scholarly journals Exploring Plant Genetic Variations with Morphometric and Molecular Markers

2021 ◽  
Author(s):  
Bushra Sadia ◽  
Faisal Saeed Awan ◽  
Fozia Saleem ◽  
Javaria Altaf ◽  
Abdullah Bin Umar ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Molecular Markers ◽  
Genetic Variability ◽  
Human Population ◽  
Crop Improvement ◽  
Genetic Variations ◽  
Germplasm Collections ◽  
Crop Germplasm ◽  
Insight Into ◽  
Sorghum Germplasm

For centuries, crop improvement has served as the basis of food security of ever increasing human population. Though vast germplasm collections are available; their exploitation for crop improvement still depends upon efficient assessment of genetic diversity. Genetic variability is the key element in adaptation of plants to varying climates. While crops with narrow genetic diversity are vulnerable to stresses. The estimation of extent and pattern of genetic variability is a prerequisite for generating superior varieties. Genetic diversity analysis generates key information to dissect genetic variations in crop germplasm with the help of morphometrical, biochemical and molecular tools. Among these, DNA markers provide a reliable and detailed insight into the similarities and differences among crops. In this chapter, we discuss the applications of phenotypic and molecular markers to probe genetic divergence in crops and present case studies that describe the significance of these tools to characterize sorghum germplasm. Furthermore, we spotlight sorghum biodiversity exploration efforts worldwide and propose future directions.

scholarly journals Potato cultivar identification using molecular markers

2010 ◽  
Vol 45 (1) ◽  
pp. 110-113 ◽  
Author(s):  
Patricia Marchezi Rosa ◽  
Tatiana de Campos ◽  
Adna Cristina Barbosa de Sousa ◽  
Danilo Augusto Sforça ◽  
Gisele Abigail Montan Torres ◽  
...  
Keyword(s):  
Molecular Markers ◽  
Microsatellite Markers ◽  
Cultivar Identification ◽  
Potato Cultivar ◽  
Polyacrylamide Gel ◽  
Potato Cultivars ◽  
Varietal Identification ◽  
Identification And Characterization

The objective of this work was to evaluate a set of microsatellite markers for varietal identification and characterization of the most widespread potato cultivars in Brazil. The DNA from 14 potato cultivars was genotyped using microsatellite markers and the alleles were scored in silver-stained polyacrylamide gel. Twenty-four microsatellite markers were evaluated, and only one locus was monomorphic. Based on band patterns, a set of two microsatellites that were able to identify and differentiate all examined cultivars was obtained.

Morphological and molecular characterization of underutilized medicinal wild ginger (Zingiber barbatum Wall.) from Myanmar

2011 ◽  
Vol 9 (4) ◽  
pp. 531-542 ◽  
Author(s):  
Noladhi Wicaksana ◽  
Syed Abdullah Gilani ◽  
Dawood Ahmad ◽  
Akira Kikuchi ◽  
Kazuo N. Watanabe
Keyword(s):  
Genetic Diversity ◽  
Growth Habit ◽  
Crop Improvement ◽  
Morphological Characters ◽  
Molecular Characteristics ◽  
Medicinal Species ◽  
Primer Sets ◽  
High Degree ◽  
Morphological And Molecular Characterization

Zingiber barbatum Wall. (family Zingiberaceae), is an underutilized medicinal plant and commonly known as ‘Meik tha-lin’ in Myanmar where it is used in the indigenous system of medicine. In the present study, 19 accessions of Z. barbatum from five provinces in Myanmar have been utilized to characterize and assess genetic diversity. Twenty-nine morphological characters were noted, including growth habit, leaf, pseudo-stem and rhizome characters. Fifteen primer sets of P450-based analogue (PBA) markers were used to reveal molecular characteristics. Of the 29 morphological characters, 22 showed a high degree of variation within wild ginger accessions, whereas 20 of these characters contributed significantly to morphological variation. Eleven amplified primer sets gave a total of 175 bands and exhibited 92.15% polymorphism across Z. barbatum accessions. Based on morphological characters and PBA markers, 19 accessions can be divided into two morphotype groups with comparatively higher genetic diversity. This information can be applied in future crop improvement, proper conservation and better use of this underutilized medicinal species.

scholarly journals Genetic diversity of Albanian pea (Pisum sativum L.) landraces assessed by morphological traits and molecular markers

2014 ◽  
Vol 50 (No. 2) ◽  
pp. 177-184 ◽  
Author(s):  
B. Gixhari ◽  
M. Pavelková ◽  
H. Ismaili ◽  
H. Vrapi ◽  
A. Jaupi ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Cluster Analysis ◽  
Molecular Markers ◽  
Morphological Traits ◽  
Principal Component ◽  
Morphological Characters ◽  
Insertion Polymorphism ◽  
Growing Seasons ◽  
And Cluster Analysis

In order to investigate the genetic diversity present in the pea germplasm stored in the Albanian genebank, we analyzed 28 local pea genotypes of Albanian origins for 23 quantitative morphological traits, as well as 14 retrotransposon-based insertion polymorphism (RBIP) molecular markers. The study of morphological characters carried out during three growing seasons (2010, 2011 and 2012) had the objective of characterization of traits useful in breeding programs. RBIP marker analysis revealed the genetic similarity in range from 0.06 to 0.45. ANOVA, principal component analysis (PCA) and cluster analysis was used to visualize the association among different traits. Most of the quantitative morphological traits showed significant differences. PCA and cluster analysis (Ward’s method) carried out for morphological traits divided the local pea genotypes into three clusters. Finally, the study identified the agronomicaly important traits which will facilitate the maintenance and agronomic evaluation of the collections.

scholarly journals Genetic diversity of cultivated Coffea arabica inbred lines assessed by RAPD, AFLP and SSR marker systems

2005 ◽  
Vol 62 (4) ◽  
pp. 366-373 ◽  
Author(s):  
Mirian Perez Maluf ◽  
Milene Silvestrini ◽  
Luciana Machado de Campos Ruggiero ◽  
Oliveiro Guerreiro Filho ◽  
Carlos Augusto Colombo
Keyword(s):  
Genetic Diversity ◽  
Molecular Markers ◽  
Genetic Variability ◽  
Inbred Line ◽  
Coffea Arabica ◽  
Ssr Marker ◽  
Cultivar Identification ◽  
Inbred Lines ◽  
Parental Origin ◽  
Commercial Species

One of the greatest problems in Coffea arabica breeding is identifying precisely any inbred line, based only on botanical and agronomical descriptors, because of the reduced genetic variability of the species, close pedigree origin, which results in small phenotypic variation. Recently, molecular markers have been used for plant germplasm characterization and identification in several commercial species. This work evaluates the reliability of three marker systems: RAPD, AFLP and SSR, to characterize the genetic variability of commercially-used Coffea inbred lines developed by the Instituto Agronômico (IAC), and their potential for cultivar identification. All methods identified polymorphisms among the cultivars. The genetic diversity recognized by the methods is very similar, although is very narrow. RAPD and SSR marker systems grouped more efficiently the evaluated cultivars according to parental origin. None of the methods allowed inbred line identification. Therefore for varietal protection, it would be necessary using a combination of botanical, agronomical and molecular markers descriptors for precise cultivar identification.

scholarly journals Genetic Diversity of Landraces and Improved Varieties of Rice (Oryza sativa L.) in Taiwan

Rice ◽  
2020 ◽  
Vol 13 (1) ◽  
Author(s):  
Ai-ling Hour ◽  
Wei-hsun Hsieh ◽  
Su-huang Chang ◽  
Yong-pei Wu ◽  
Han-shiuan Chin ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Genetic Variation ◽  
Indigenous Peoples ◽  
Oryza Sativa L ◽  
Crop Improvement ◽  
Genetic Erosion ◽  
Germplasm Conservation ◽  
Gene Pools ◽  
Improved Varieties ◽  
Breeding Goals

Abstract Background Rice, the most important crop in Asia, has been cultivated in Taiwan for more than 5000 years. The landraces preserved by indigenous peoples and brought by immigrants from China hundreds of years ago exhibit large variation in morphology, implying that they comprise rich genetic resources. Breeding goals according to the preferences of farmers, consumers and government policies also alter gene pools and genetic diversity of improved varieties. To unveil how genetic diversity is affected by natural, farmers’, and breeders’ selections is crucial for germplasm conservation and crop improvement. Results A diversity panel of 148 rice accessions, including 47 cultivars and 59 landraces from Taiwan and 42 accessions from other countries, were genotyped by using 75 molecular markers that revealed an average of 12.7 alleles per locus with mean polymorphism information content of 0.72. These accessions could be grouped into five subpopulations corresponding to wild rice, japonica landraces, indica landraces, indica cultivars, and japonica cultivars. The genetic diversity within subpopulations was: wild rices > landraces > cultivars; and indica rice > japonica rice. Despite having less variation among cultivars, japonica landraces had greater genetic variation than indica landraces because the majority of Taiwanese japonica landraces preserved by indigenous peoples were classified as tropical japonica. Two major clusters of indica landraces were formed by phylogenetic analysis, in accordance with immigration from two origins. Genetic erosion had occurred in later japonica varieties due to a narrow selection of germplasm being incorporated into breeding programs for premium grain quality. Genetic differentiation between early and late cultivars was significant in japonica (FST = 0.3751) but not in indica (FST = 0.0045), indicating effects of different breeding goals on modern germplasm. Indigenous landraces with unique intermediate and admixed genetic backgrounds were untapped, representing valuable resources for rice breeding. Conclusions The genetic diversity of improved rice varieties has been substantially shaped by breeding goals, leading to differentiation between indica and japonica cultivars. Taiwanese landraces with different origins possess various and unique genetic backgrounds. Taiwanese rice germplasm provides diverse genetic variation for association mapping to unveil useful genes and is a precious genetic reservoir for rice improvement.

β-Amyrin Synthase1 Controls the Accumulation of the Major Saponins Present in Pea (Pisum sativum)

2021 ◽  
Author(s):  
Vanessa Vernoud ◽  
Ludivine Lebeigle ◽  
Jocelyn Munier ◽  
Julie Marais ◽  
Myriam Sanchez ◽  
...  
Keyword(s):  
Pisum Sativum ◽  
Bitter Taste ◽  
Crop Improvement ◽  
Functional Protein ◽  
Saponin Biosynthesis ◽  
Physiological Quality ◽  
Pea Seeds ◽  
Identification And Characterization ◽  
Pea Seed

Abstract The use of pulses as ingredients for the production of food products rich in plant proteins is increasing. However, protein fractions prepared from pea or other pulses contain significant amounts of saponins, glycosylated triterpenes which can impart an undesirable bitter taste when used as an ingredient in foodstuffs. In this paper, we describe the identification and characterization of a gene involved in saponin biosynthesis during pea seed development, by screening mutants obtained from two Pisum sativum TILLING (Targeting Induced Local Lesions in Genomes) populations in two different genetic backgrounds. The mutations studied are located in a gene designated PsBAS1 (β-amyrin synthase1) which is highly expressed in maturing pea seeds and which encodes a protein previously shown to correspond to an active β-amyrin synthase. The first allele is a nonsense mutation, while the second mutation is located in a splice site and gives rise to a mis-spliced transcript encoding a truncated, non-functional protein. The homozygous mutant seeds accumulated virtually no saponin without affecting seed nutritional or physiological quality. Interestingly, BAS1 appears to control saponin accumulation in all other tissues of the plant examined. These lines represent a first step in the development of pea varieties lacking bitterness off-flavours in their seeds. Our work also shows that TILLING populations in different genetic backgrounds represent valuable genetic resources for both crop improvement and functional genomics.

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